2001 Chevy Silverado 1500 v6 won't start


I have a 2001 Chevy Silverado 1500. I went to start it today and it wouldn’t do anything…acted like it wanted to turn over but nothing. But something was running under the hood sounded like it was near the oil pan? I unhooked the neg, battery cable to shut it off. Then I went to hook the battery up and it sparked a lot and the terminal looks like it wants to weld itself to battery. All the dashboard lights up, but check engine light is on. Hoping it’s nothing big. Could it be the battery or alternator? It has 124,000 miles on it, I use it everyday and have a routine maintenance done every time I change the oil. All fluid levels look good. I have been through 2 batteries in the past 4 years though. Thanks.